Black had always believed that the pain would make him stronger. However, he was not prepared for this type of pain.
Zamasu hovered above him, his immortal body unscathed from the battle that had just ensued. He looked down upon him, as if he saw him as just another mortal waiting to be cleansed.
He hated that.
The false saiyan had put up as good of a fight as ever, despite knowing it was futile against immortality. The others—Trunks, Goku, and Vegeta—had merely watched in both awe and confusion as the two gods went for each other's throats. They didn't understand what had happened between them. They didn't know that Black was technically on their side, now, as much as he loathed to admit it.
Now, as Black breathed with heavy breaths and stood on the ground feeling as though his legs were on the verge of collapse , he continued to do everything in his power to stand strong against his counterpart. Maybe, he thought, if he fought against him as hard as the mortals did, he, too, would see the error of his ways and join him once again. Perhaps they could work together to right the wrongs they'd committed upon the cosmos.
As Zamasu readied his energy sword, those thoughts became fleeting. It became more and more clear to Black that this future incarnation of himself was too overcome with thoughts of justice and purity to listen to reason anymore. He supposed it was time to give up trying to save him.
Soon enough, the fight continued.